Torsion and its interaction with other internal forces in EN 1993-1-1: a new approach

This is the accepted version of the following article: [Real, E., Bordallo, J. and Real, E. (2016), Torsion and its interaction with other internal forces in EN 1993-1-1 – a new approach. Steel Construction, 9: 240–248. doi:10.1002/stco.201500005], which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/stco.201500005/abstractThis paper presents and clarifies the treatments included in EN 1993-1-1, relating to checking the resistance of the steel cross-sections under torsion and its interaction with other internal forces. Specifically, the origin of the formulations for shear-torsion interaction, which was not found in the literature, is presented. Furthermore, a very simple formulation based on the expressions used for shear-torsion interaction is developed, in order to take into account bending-warping torsion interaction for symmetrical double T cross-sections (IP and HE steel profiles). Such formulation overcomes the overly conservative approach stated in EN 1993-1-1, for Class 1 and Class 2 cross-sections (plastic and compact cross-sections). Finally, a rigorous method for the determination of the bending resistance of cross-sections is proposed, considering the interaction with shear and torsion. The proposal is well suited to the concept of cross-sectional class and it is perfectly consistent with the approaches set out to consider the bending-shear and bending-warping torsion interactions.Peer ReviewedPostprint (author's final draft

Stainless steel plate girders subjected to shear buckling at normal and elevated temperatures

The final publication is available at Springer via http://dx.doi.org/10.1007/s10694-016-0602-6Numerical simulations have been widely applied, for the determination of the resistance of steel structural elements, when experimental analysis are not possible (due to cost or size limitations) or when parametric studies with high number of variables are needed. However, the numerical models must be properly validated with experimental tests in order to deliver reliable studies. With the purpose of studying the behaviour of stainless steel plate girders in fire situation, a total of 34 experimental tests from the literature have been numerically modelled. The tested girders had different configurations: rigid and non-rigid end posts, 2 and 4 panels, and transversal and longitudinal stiffeners were considered. Comparative analyses between those experimental and numerical results have been done. Good approximations to the experimental results at normal temperatures have been achieved with differences on average lower than 5%. Afterwards, the developed numerical model has been used to perform a sensitivity analysis on the influence of the initial geometric imperfections at both normal and elevated temperatures, considering different values for its maximum amplitudes, concluding that 10% of the web thickness is an appropriate value for the maximum amplitude of the geometric imperfections when modelling experimental tests. The effect of the residual stresses has also been analysed, being obtained differences lower than 2%. Finally, comparisons between the numerical results and the Eurocode 3 design procedures have been performed considering different uniform elevated temperatures.Peer ReviewedPostprint (author's final draft

Experimental study on ferritic stainless steel simply supported and continuous beams

Development of efficient design guidance for stainless steel structures is key for the increased use of this corrosion-resistant material by considering both nonlinear behaviour and strain hardening into resistance prediction expressions, together with the moment redistribution in indeterminate structures. With the aim of analysing the bending moment redistribution capacity of ferritic stainless steel beams, a comprehensive experimental programme on continuous beams is presented. These tests contribute to the assessment of EN1993-1-4 specifications, where no plastic design is allowed, and the classical and new plastic design methods available in the literature for indeterminate stainless steel structures. Four three-point and eight four-point bending tests are also reported for the assessment of current codified and revised cross-sectional classification limits, analysing the different methods for the prediction of the ultimate bending capacities of ferritic hollow sections. Additional test results reported by other authors in different stainless steel grades and carbon steel are also studied and presented. The analysis indicates that Class 1 cross-sectional classification limits are too optimistic for ferritic stainless steels and further research is needed for the extension of plastic design to these grades, although promising predictions of ultimate loads are obtained for austenitic and lean duplex stainless steels.Peer ReviewedPostprint (author's final draft

Numerical modelling of steel plate girders at normal and elevated temperatures

The main goal of this study is to increase the knowledge on the behaviour of steel plate girders subjected to shear buckling at both normal and elevated temperatures. Hence, numerical models were duly validated with experimental tests from the literature. Experimental tests on steel plate girders with different configurations were numerically reproduced, showing a good agreement between numerical and experimental results. Afterwards, applying the validated numerical models, sensitivity analyses on the influence of initial imperfections were performed. Different values for the maximum amplitude of geometric imperfections were considered and residual stresses were also taken into account. Finally, the effect of the end supports configuration was also studied aiming to understand the strength enhancement given by the rigid end support at normal temperature and evaluating if that strength enhancement is maintained in case of fire.Peer ReviewedPostprint (author's final draft

Design of welded stainless steel I-shaped members subjected to shear

This paper aims to develop design methods for the shear strength of welded stainless steel I-shaped members. The current American AISC Design Guide 27 has been published for Structural Stainless Steel, and it refers to the specification ANSI/AISC 360-16 for structural steel buildings for the shear strength without considering tension field action (TFA). All the available test data on stainless steel plate girders were collected from literatures and employed to assess the provisions in the Design Guide 27, as well as the codified ones in Eurocode 3 Part 1.4. Based on the test results and obtained comparisons, two new proposals for unstiffened webs or webs with transverse stiffeners widely spaced (without TFA), and for interior webs with stiffeners spaced at 3hw or smaller (considering TFA) were developed and presented to match the format of the expressions in ANSI/AISC 360-16 for stainless steel webs under shear. Reliability analysis was further performed to calculate the Load and Resistance Factor Design (LRFD) resistance factors determined by the new proposals and to further justify the target factor in AISC Design Guide 27 for structural stainless steel.Peer ReviewedPostprint (author's final draft

Integrating Sustainability snd Social Commitment (S&SC) competences in the curriculum at the Barcelona School of Civil Engineering

The importance of integrating the Sustainable Development Goals (SDG) in the curriculum of all the bachelor and master degrees at UPC has been legally and institutionally recognised. At the Barcelona School of Civil Engineering, issues such as professional ethics, environmental impacts of infrastructures, respect for cultural diversity and gender perspective are currently cross-cutting competences highlighted and stated in the study plans as a transversal competence on Sustainability and Social Commitment (S&SC). However, its effective implementation requires significant teaching efforts in order to adapt academic curricula, so far limited to individual non- coordinated initiatives. The launch of the “ODS-Camins Toolkit” project (Toolkit for the Promotion of SDG in the Civil and Environmental Engineering Fields) seeks to encourage the implementation of teaching innovation practices that contribute to the deployment and assessment of S&CS competences. The aim of the project is to exchange experiences, develop new practices, and draft a common pathway for the promotion and implementation of the SDGs in the field of civil and environmental engineering studies. The paper will explain the experience of this one-year project, highlighting barriers, challenges, and sharing the lessons learned with the final purpose of involving all the community in the years to come. It will also present the Toolkit for the Promotion of SDGs in the Civil and Environmental Engineering FieldsPostprint (published version

Reptes actuals per a la funció i la formació docent del professorat universitari a la UPC

Peer Reviewe

Resistance of hybrid steel plate girders subjected to patch loading

Hybrid girders have proven to be an economical alternative to homogeneous girders since they provide a greater flexural capacity. One of the potential applications of hybrid steel plate girders is their usage in bridge construction. One of the potential constructive methods of these bridges is the push launch method, in which patch loads may condition the design. The aim of this paper is to present advanced conclusions of a research work dealing simultaneously with these two fields; the hybrid typology when subjected to the particular case of patch loading. The most remarkable results of the research work are pointed out. On the one hand, it is shown that the influence of the fyf/fyw ratio (namely, the hybrid grade) is negligible for girders with largely spaced transverse stiffeners. On the other hand, it is shown that this influence can be significant if the transverse stiffeners are closely spaced. Suggestions for considering these findings on design codes are provided at the end paper.Peer ReviewedPostprint (published version

Transversally and longitudinally stiffened steel plate girders subjected to patch loading

This article presents some observations related to the phenomenon that occurs when transversally and longitudinally stiffened steel plate girders are subjected to patch loading. The failure mechanism differs considerably for the particular structural case of girders with largely spaced transverse stiffeners, which have been studied thoroughly in last decades. Steel plate girders with closely spaced stiffeners are occasionally found in bridge design and for such cases, the current EN1993-1-5 rules underestimate the strength of the webs to transverse forces. Research work on girders with closely spaced transverse stiffeners is available but for such cases, the web plates are longitudinally unstiffened. Some comparisons between the results obtained and those provided by EN1993-1-5 are discussed. Preliminary results suggest that the resistance of densely stiffened steel girders (both transversally and longitudinally) must be studied and subsequently revised accordingly. In addition, it is pointed out that a certain degree of imperfection sensitivity is inferred from the results. Further studies on this topic are necessary.Peer ReviewedPostprint (author's final draft

Pre-normative recommendations for the system-based direct design of stainless steel frames using advanced analysis

This document includes the pre-normative recommendations developed in the NewGeneSS research project for the design of stainless steel frames using advanced analysisThe research project NewGeneSS, the acronym of “NEW GENEration design methods for Stainless steel Structures” was financed by the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Actions (2018). The NewGeneSS project aimed at developing the basis of system-based direct design approaches for stainless steel structures in the European framework by calibrating suitable system safety factors from rigorous structural reliability considerations, and at delivering the pre-normative design recommendations included in this document.The project leading to this document has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant Agreement No. 842395 (NewGeneSS project).Preprin